Giant Screwdriver Restoration

[Rhyolith]

Guys could take the discussion about torque to its own thread please.

Thanks

 

[ED65]

Guys could take the discussion about torque to its own thread please.

Done: advantage-of-longer-screwdrivers-more-leverage-or-t99646.html

 

[ED65]

You mean let it oxidise a bit? Probably not since it would take a while and I don't like thr idea of corroding it.

You could deliberately cause it to flash-rust, then stabilise the rust. This in essence recreates 'patina' on steel.

 

[AndyT]

Afaik, when tools like this were made, they would have been ground on a big natural stone wheel, by a skilled grinder sitting astride the wheel. That would get the forging properly straight, or more likely, nicely tapered.

There was then a second process, known as glazing, which took out the scratches and left a nice surface, which could be from something like a modern " brushed" finish, up to a mirror finish.

The nearest equivalent power tool (assuming you don't want to install line shafting, a water supply and a way of lifting great lumps of stone into place) would be the belt sander.

In the right hands, they can produce a lovely even finish on steel.

But for a one off, I would try just working through the grits on wet and dry paper, with a cork block and plenty of water or white spirit, until you get the appearance you want.

 

[ED65]

Wouldn't something harder than cork be better for the block Andy? I'm thinking the slight give of cork might tend to dub the edges more than would be desirable, but I defer to your far greater experience in this area.

 

[AndyT]

You could be right Ed. I was thinking of what I would use, aiming at keeping an aged look, but for a pristine, new look a hard wooden block would avoid any rounding over of the edges.

 

[Limey Lurker]

>A long vertical bar will give more torque.
>A long radial handle will give more foot lbs for the effort expended.
>dont confuse the two.


Torque is measured in foot-pounds (or it's Metric equivelant). A long "vertical" bar will have NO effect on torque.
A long (or ANY length) radial bar will only give the same number of foot-pounds as are applied to the bar.

 

[Yorkshire Sam]

These engineers screwdrivers are quite common. A typical use would be for unscrewing deck plates in machinery spaces ie ships. The reason for the length is to save bending too much and the flat so that a spanner could apply any extra torque needed for stuck screws which were usually quite large diameter ( although short in length) with flat heads chamfered heads to keep the machine plates flat.

Even 'new; they were seldom shiny.

 

[Jacob]

Yes and there was a whole technology of wood plus metal which has more or less disappeared. Boats, ships, railway wagons, silos, industrial plant, farm machinery, often made with timber and metal plates with large (but short) screws as well as longer coach screws (with square heads) ,rivets, bolts etc.

There is a size limit on slotted screws - 14 perhaps, above which you'd need the leverage of a spanner on a nut

 

[bugbear]

These engineers screwdrivers are quite common. A typical use would be for unscrewing deck plates in machinery spaces ie ships. The reason for the length is to save bending too much and the flat so that a spanner could apply any extra torque needed for stuck screws which were usually quite large diameter ( although short in length) with flat heads chamfered heads to keep the machine plates flat.

Even 'new; they were seldom shiny.

Thanks for that - very credible.

BugBear

 

[AndyT]

Another answer to the question 'why did anyone need such a long screwdriver?' was provided by this Marples ad from 1938 -

- they are what you need to keep a reputation up!

 

[Rhyolith]

I have sanded it down with wet and dry down to 600p, I mounted that on one of those rubber drill mounted pad things... which worked remarkably well! I left fairly uniform marks (more uniform than my hand sanding) and was quick.. thought it wrecked the paper quickly too so I don't think I will be doing it again.

After that I buffed it with a coarse polish and then rubbed oil all over to give a more matted affect and protect from rust.

There are a few swirly scratches that I would rather were not there but overall its pretty nice and still has plenty of age marks (they don't appear to well in the photo).

Anyways here it is:
Giant Screwdriver by Rhyolith, on Flickr
Giant Screwdriver by Rhyolith, on Flickr

To give an impression of just how ludicrously large it is, here is a Yankee 131 (largest size of yankee) for comparison:
Giant Screwdriver & Large Yankee by Rhyolith, on Flickr

 

[Jacob]

Yes and there was a whole technology of wood plus metal which has more or less disappeared. Boats, ships, railway wagons, silos, industrial plant, farm machinery, often made with timber and metal plates with large (but short) screws as well as longer coach screws (with square heads) ,rivets, bolts etc.

There is a size limit on slotted screws - 14 perhaps, above which you'd need the leverage of a spanner on a nut

Oops just got to revise that! I've dug out a box of Nettlefold screws size 20 x 1 1/4". I knew they were there I'd forgotten how big they were!

 

[AndyT]

My 1935 Buck and Hickman catalogue lists countersunk steel screws up to No 40 (for lengths of 3 1/2" to 5") with No 32 available in lengths of 1 1/2" to 2 3/4".

For brass, No 32 was the largest size, 3" to 6" long.

Anyone got any of these giants waiting for the right job to come up?

 

[Jacob]

There you go then - bigger and bigger!

 

[bugbear]

The upper section of the blade looks as if it's intended to be a handle - or at least it's shaped for it.

But that makes no sense.

Am I over interpreting a decorative shape?

BugBear

 

[Jacob]

Struck me as handle, and makes sense - two handed steadying grip.

 

[morturn]

A lot of stationary steam engines used countersunk screws in their construction. I have seen engineers use this type of screwdriver on this type of screw. They will often also use an adjustable spanner just above the blade of the screwdriver to get additional leverage.

Of course as with all us woodworkers, they would line up all of the slots to face the same direction. Only in this case it means taking the screw out and giving the countersink tool a few extra turns just to get things to line up.

 

[bugbear]

Of course as with all us woodworkers, they would line up all of the slots to face the same direction. Only in this case it means taking the screw out and giving the countersink tool a few extra turns just to get things to line up.

That means if you take the screws out, they'd have to go back in the same holes for the slots to still line up, assuming a random start to the cut threads w.r.t. the slot.

BugBear

 

[AndyT]

The upper section of the blade looks as if it's intended to be a handle - or at least it's shaped for it.

But that makes no sense.

Am I over interpreting a decorative shape?

BugBear

I think maybe you are, and that the screwdriver/turnscrew is one of the few tools in the British tradition where there was generally a little bit of decoration.

By way of evidence, here is a gallery of such tools, from a printed catalogue by Arnold & Walker in 1978, back in the pre-www 'dark ages' of tool collecting:

Most of them have a bit of waisting, some have a filed detail. The shaping is the sort of thing that would have been natural for a smith to do, when making one of these at the anvil, and my feeling is that if you left all the shaping out, you'd have such a grossly plain piece of work that a smith would take no pride in it. It needs some shape to make it a proper looking tool.

I wonder when this style stopped being made? Probably when the sort of strong wood/iron construction pointed out by Jacob became obsolete - around about the second world war. That may well mean that even the commercially branded examples would have been hand-made, one by one, at the anvil, and never had the sort of compromises to the shape that drop-forging brought in for smaller screwdrivers and chisels.

Btw, no 140 was described as 'Over 36" long. Stamped Tyzack 1917' and was offered for sale at £10.